U.S. patent number 8,021,205 [Application Number 12/354,371] was granted by the patent office on 2011-09-20 for organic light-emitting diode display device and method of manufacturing the same.
This patent grant is currently assigned to Samsung Electronics Co., Ltd.. Invention is credited to Chang-Woong Chu, Won-Hoe Koo, Joo-Hyeon Lee, Chang-Mo Park.
United States Patent |
8,021,205 |
Lee , et al. |
September 20, 2011 |
Organic light-emitting diode display device and method of
manufacturing the same
Abstract
An organic light-emitting diode ("OLED") device includes an
organic light-emitting substrate part and a protective cover part.
The organic light-emitting substrate part includes a base substrate
and an OLED display portion formed on the base substrate to display
an image. The protective cover part includes a first frit glass
disposed on the OLED display portion to cover the OLED display
portion, and a second frit glass formed around a periphery of the
first frit glass. The second frit glass is connected to the first
frit glass.
Inventors: |
Lee; Joo-Hyeon (Yongin-si,
KR), Chu; Chang-Woong (Suwon-si, KR), Park;
Chang-Mo (Seoul, KR), Koo; Won-Hoe (Suwon-si,
KR) |
Assignee: |
Samsung Electronics Co., Ltd.
(KR)
|
Family
ID: |
40954471 |
Appl.
No.: |
12/354,371 |
Filed: |
January 15, 2009 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20090206739 A1 |
Aug 20, 2009 |
|
Foreign Application Priority Data
|
|
|
|
|
Feb 18, 2008 [KR] |
|
|
2008-14319 |
|
Current U.S.
Class: |
445/25;
313/512 |
Current CPC
Class: |
H01L
51/5246 (20130101); Y02E 10/549 (20130101) |
Current International
Class: |
H05B
33/04 (20060101); H01L 51/40 (20060101) |
Field of
Search: |
;313/512,504
;445/25 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
2002-280169 |
|
Sep 2002 |
|
JP |
|
100671645 |
|
Jan 2007 |
|
KR |
|
100712177 |
|
Apr 2007 |
|
KR |
|
Primary Examiner: Guharay; Karabi
Attorney, Agent or Firm: Cantor Colburn LLP
Claims
What is claimed is:
1. A method of manufacturing an organic light-emitting diode
display device, the method comprising: forming an organic
light-emitting substrate part, the forming the organic
light-emitting substrate part comprising: forming a base substrate;
and forming an organic light-emitting diode display portion on the
base substrate to display an image thereon; and forming a
protective cover part comprising a first frit glass disposed on the
organic light-emitting diode display portion to cover the organic
light-emitting diode display portion and a second frit glass formed
around a periphery of the first frit glass and connected to the
first frit glass, wherein forming the protective cover part
comprises: forming the first frit glass on a cover substrate;
forming the second frit glass on a cover substrate; connecting the
cover substrate to the organic light-emitting substrate part; and
separating the cover substrate from the first frit glass and the
second frit glass.
2. The method of claim 1, wherein the forming the first frit glass
and the forming the second frit glass each comprises: forming a
first frit paste on the cover substrate; forming a second frit
paste on the cover substrate around a periphery of the organic
light-emitting diode display portion defined by the first frit
paste; drying the first frit paste and the second frit paste; and
firing the first frit paste and the second frit paste to form the
first frit glass and the second frit glass, respectively.
3. The method of claim 2, wherein the forming the first frit glass
and the forming the second frit glass further comprises partially
curing the second frit glass and completely curing the first frit
glass by: applying a laser beam to a boundary area between the
first frit glass and the second frit glass, the boundary area
including only a portion of the second frit glass such that only
the portion of the second frit glass included in the boundary area
is cured, and applying the laser beam to an entire area of the
first frit glass to cure the entire area of the first frit
glass.
4. The method of claim 2, wherein the first frit paste and the
second frit paste each comprises: frit powder particles; binder
particles interposed between the frit powder particles; and filler
particles interposed between the frit powder particles, wherein the
forming the first frit glass and the forming the second frit glass
each further comprises dissolving the frit powder particles, the
binder particles and the filler particles using a solvent.
5. The method of claim 4, wherein the drying the first frit paste
and the second frit paste and the firing the first frit paste and
the second frit paste each comprises: drying the first frit paste
and the second frit paste at a first temperature to remove the
solvent therefrom; and firing the first frit paste and the second
frit paste, from which the solvent is removed, at a second
temperature greater than the first temperature, to remove the
binder particles from the first frit paste and the second frit
paste.
6. The method of claim 5, wherein the first temperature has a range
of approximately 180.degree. C. to approximately 220.degree. C.,
and the second temperature has a range of approximately 400.degree.
C. to approximately 600.degree. C.
7. The method of claim 1, wherein the connecting the cover
substrate to the organic light-emitting substrate part comprises:
aligning the cover substrate with the organic light-emitting
substrate part such that the first frit glass covers the organic
light-emitting diode display portion; and applying a laser beam to
the second frit glass to connect the second frit glass to the base
substrate.
8. The method of claim 1, wherein the forming the protective cover
part further comprises: forming a frit cover layer between the
cover substrate and each of the first frit glass and the second
frit glass.
9. The method of claim 8, wherein forming the protective cover part
further comprises, prior to separating the cover substrate from the
first and second frit glasses, irradiating a laser beam onto an
entire area of the frit cover layer.
10. The method of claim 9, wherein the frit cover layer includes a
single layer comprising one of an inorganic insulation layer and a
metal layer.
11. The method of claim 9, wherein the frit cover layer includes a
double layer comprising an inorganic insulation layer and a metal
layer.
12. The method of claim 11, wherein the metal layer is formed on
the cover substrate, and the inorganic insulation layer is formed
between the metal layer and each of the first frit glass and the
second frit glass.
13. The method of claim 1, wherein a thickness of the second frit
glass is greater than a corresponding thickness of the first frit
glass.
Description
This application claims priority to Korean Patent Application No.
2008-14319, filed on Feb. 18, 2008, and all the benefits accruing
therefrom under 35 U.S.C. .sctn.119, the contents of which in its
entirety are herein incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a display device and a method of
manufacturing the display device. More particularly, the present
invention relates to an organic light-emitting diode ("OLED")
display device including OLEDs and a method of manufacturing the
OLED display device.
2. Description of the Related Art
An organic light-emitting diode ("OLED") display device typically
includes a base substrate, an OLED display portion formed on the
base substrate to display an image thereon, and a cover substrate
disposed opposite to, e.g., facing, the base substrate.
The OLED display portion generally includes a plurality of unit
pixels, and each unit pixel of the plurality of unit pixels
includes an OLED which displays a particular color, for example.
Generally, the OLED display portion is easily adversely affected by
external moisture entering the OLED display device or external
impact, for example.
In order to protect the OLED display portion from the external
moisture, a space between the base substrate and the cover
substrate is sealed using frit glass cured by a laser beam, for
example. Specifically, the frit glass is formed along an outline,
e.g., a periphery, of the cover substrate and is combined with the
base substrate to protect the OLED display portion from the
external moisture.
As a size of the cover substrate increases, however, a middle
portion of the cover substrate sags under an increasing load
applied to the OLED display portion due to the increased size of
the cover substrate. As a result, the cover substrate impacts the
OLED display portion.
In addition, gas generated in a process of curing the frit glass
with the laser beam has a negative influence on the OLED display
portion.
Because of the abovementioned disadvantages, the typical OLED
display portion is required to be covered by a separate protective
layer which protects the OLED display portion from impact by the
cover substrate and the gas generated from curing the frit
glass.
As a result, manufacturing costs of the OLED display device
increase and manufacturing processes of the OLED display device are
complicated, since the OLED display device is required to include
the cover substrate and the protective layer.
Thus, a need exists to develop an OLED display device which
overcomes the aforementioned problems.
BRIEF SUMMARY OF THE INVENTION
Exemplary embodiments of the present invention obviate the problems
described above. In particular, exemplary embodiments of the
present invention provide an organic light-emitting diode ("OLED")
display device which protects an OLED display portion thereof and,
as a result, includes reduced manufacturing costs, among other
advantages.
Exemplary embodiments of the present invention also provide a
method of manufacturing the OLED display device having the
above-mentioned advantages.
An OLED display device according to an exemplary embodiment of the
present invention includes an organic light-emitting substrate part
and a protective cover part.
The organic light-emitting substrate part includes a base substrate
and an OLED display portion formed on the base substrate to display
an image. The protective cover part includes a first frit glass
disposed on the OLED display portion to cover the OLED display
portion and a second frit glass formed around a periphery of the
first frit glass. The second frit glass is connected to the first
frit glass.
The first and second frit glasses have a moisture permeation
resistance. The first frit glass and the second frit glass may each
include substantially a same material. Each of the first frit glass
and the second frit glass may include frit powder particles and
filler particles interposed between the frit powder particles.
The organic light-emitting substrate part may further include a
protective layer formed between the OLED display portion and the
first frit glass to cover and protect the OLED display portion.
The protective cover part may further include a frit cover layer
formed on the first frit glass and the second frit glass.
In an alternative exemplary embodiment of the present invention, a
method of manufacturing an OLED display device includes forming an
organic light-emitting substrate part by forming a base substrate
and then forming an OLED display portion on the base substrate to
display an image thereon. Then, a protective cover part is formed,
the protective cover part including a first frit glass disposed on
the OLED display portion to cover the OLED display portion and a
second frit glass formed around a periphery of the first frit glass
and connected to the first frit glass.
To form the protective cover part, a cover substrate is formed, and
the first frit glass and the second frit glass are then formed on
the cover substrate. The cover substrate may then be connected to
the organic light-emitting substrate part such that the first frit
glass covers the OLED display portion. Thereafter, the cover
substrate may be separated from the first frit glass and the second
frit glass.
To form the first frit glass and the second frit glass, a first
frit paste may be formed on the cover substrate, and then a second
frit paste may be formed on the cover substrate around a periphery
of the OLED display portion defined by the first frit paste.
Thereafter, the first frit paste and the second frit paste may be
dried and fired to form the first frit glass and the second frit
glass, respectively. The forming the first frit glass and the
forming the second frit glass may further comprise partially curing
the second frit glass and completely curing the first frit glass by
applying a laser beam to a boundary area between the first frit
glass the second frit glass, the boundary area including only a
portion of the second frit glass such that only the portion of the
second frit glass included in the boundary area is cured, and
applying the laser beam to an entire area of the first frit glass
to cure the entire area of the first frit glass.
The first frit paste and the second frit paste may each include
frit powder particles, binder particles interposed between the frit
powder particles and filler particles interposed between the frit
powder particles. The forming the first frit glass and the forming
the second frit glass may each further comprise dissolving the frit
powder particles, the binder particles and the filler particles
using a solvent.
To dry and fire the first frit paste and the second frit paste, the
first frit paste and the second frit paste may each be dried at a
first temperature to remove the solvent therefrom. Then, the first
frit paste and the second frit paste, from which the solvent is
removed, may each be fired at a second temperature greater than the
first temperature to remove the binder particles therefrom.
In an exemplary embodiment of the present invention, the first
temperature has a range of approximately 180.degree. C. to
approximately 220.degree. C., and the second temperature has a
range of approximately 400.degree. C. to approximately 600.degree.
C.
To connect the cover substrate to the organic light-emitting
substrate part, the cover substrate may be aligned with the organic
light-emitting substrate part such that the first frit glass covers
the OLED display portion. Then, a laser beam may be applied to the
second frit glass to connect the second frit glass to the base
substrate.
When the protective cover part is formed, a frit cover layer may be
formed between the cover substrate and each of the first frit glass
and the second frit glass. Further, the cover substrate maybe
separated from the first frit glass and the second frit glass after
a laser beam is irradiated onto an entire area of the frit cover
layer.
In an exemplary embodiment, the frit cover layer may include a
single layer having one of an inorganic insulation layer and a
metal layer.
In an alternative exemplary embodiment, the frit cover layer may
include a double layer including an inorganic insulation layer and
a metal layer. In this case, the metal layer may be formed on the
cover substrate, and the inorganic insulation layer may be formed
between the metal layer and each of the first frit glass and the
second frit glass.
A thickness of the second frit glass may be greater than a
corresponding thickness of the first frit glass.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other aspects, features and advantages of the present
invention will become more readily apparent by describing in
further detail exemplary embodiments thereof with reference to the
accompanying drawings, in which:
FIG. 1 is a plan view illustrating an organic light-emitting diode
("OLED") display device according to an exemplary embodiment of the
present invention;
FIGS. 2 and 3 are partial cross-sectional views taken along line
I-I' in FIG. 1;
FIG. 4 is a schematic circuit diagram illustrating a unit pixel of
an OLED display portion of the OLED display device according to the
exemplary embodiment of the present invention shown in FIG. 1;
FIG. 5 is a partial cross-sectional view illustrating a process of
forming an organic light-emitting substrate part of the OLED
display device according to the exemplary embodiment of the present
invention shown in FIG. 1;
FIGS. 6 and 7 are partial cross-sectional views illustrating a
process of forming a frit cover layer on a cover substrate of an
OLED display device according to an exemplary embodiment of the
present invention;
FIG. 8 is a partial cross-sectional view illustrating a process of
forming a first frit glass on the frit cover layer of the OLED
display device according to the exemplary embodiment of the present
invention shown in FIG. 6;
FIG. 9 is a partial cross-sectional view illustrating a process of
forming a second frit glass on the frit cover layer of the OLED
display device according to the exemplary embodiment of the present
invention shown in FIG. 7;
FIGS. 10A and 10B are partial cross-sectional views illustrating
internal states, before and after firing, respectively, of both the
first frit glass and the second frit glass of the OLED display
device according to the exemplary embodiment of the present
invention shown in FIGS. 8 and 9;
FIG. 11 is a partial cross-sectional view illustrating a process of
applying a laser beam to both the first frit glass and the second
frit glass of the OLED display device according to the exemplary
embodiment of the present invention shown in FIG. 9;
FIG. 12 is a partial cross-sectional view illustrating a process of
coupling the organic light-emitting substrate part of the OLED
display device according to the exemplary embodiment of the present
invention shown in FIG. 5 to the protective cover part of the OLED
display device according to the exemplary embodiment of the present
invention shown in FIG. 11;
FIG. 13 is a partial cross-sectional view illustrating a process of
applying a laser beam to the second frit glass of the OLED display
device according to the exemplary embodiment of the present
invention shown in FIG. 12;
FIGS. 14A and 14B are partial cross-sectional views of area "A" in
FIG. 13, illustrating internal states, before and after applying
the laser beam, respectively, of the second frit glass of the OLED
display device according to the exemplary embodiment of the present
invention shown in FIG. 13; and
FIG. 15 is a partial cross-sectional view illustrating a process of
separating the cover substrate of the OLED display device according
to the exemplary embodiment of the present invention shown in FIG.
14 from the first frit glass and the second frit glass.
DETAILED DESCRIPTION OF THE INVENTION
The invention will now be described more fully hereinafter with
reference to the accompanying drawings, in which exemplary
embodiments of the invention are shown. The present invention may,
however, be embodied in many different forms and should not be
construed as limited to the embodiments set forth herein. Rather,
these embodiments are provided so that this disclosure will be
thorough and complete, and will fully convey the scope of the
invention to those skilled in the art. Like reference numerals
refer to like elements throughout.
It will be understood that when an element is referred to as being
"on" another element, it can be directly on the other element or
intervening elements may be present therebetween. In contrast, when
an element is referred to as being "directly on" another element,
there are no intervening elements present. As used herein, the term
"and/or" includes any and all combinations of one or more of the
associated listed items.
It will be understood that although the terms "first," "second,"
"third" etc. may be used herein to describe various elements,
components, regions, layers and/or sections, these elements,
components, regions, layers and/or sections should not be limited
by these terms. These terms are only used to distinguish one
element, component, region, layer or section from another element,
component, region, layer or section. Thus, a first element,
component, region, layer or section discussed below could be termed
a second element, component, region, layer or section without
departing from the teachings of the present invention.
The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. As used herein, the singular forms "a", "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" and/or "comprising," or "includes"
and/or "including," when used in this specification, specify the
presence of stated features, regions, integers, steps, operations,
elements and/or components, but do not preclude the presence or
addition of one or more other features, regions, integers, steps,
operations, elements, components and/or groups thereof.
Furthermore, relative terms, such as "lower" or "bottom" and
"upper" or "top" may be used herein to describe one element's
relationship to other elements as illustrated in the Figures. It
will be understood that relative terms are intended to encompass
different orientations of the device in addition to the orientation
depicted in the Figures. For example, if the device in one of the
figures is turned over, elements described as being on the "lower"
side of other elements would then be oriented on the "upper" side
of the other elements. The exemplary term "lower" can, therefore,
encompass both an orientation of "lower" and "upper," depending
upon the particular orientation of the figure. Similarly, if the
device in one of the figures were turned over, elements described
as "below" or "beneath" other elements would then be oriented
"above" the other elements. The exemplary terms "below" or
"beneath" can, therefore, encompass both an orientation of above
and below.
Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which the present
invention belongs. It will be further understood that terms, such
as those defined in commonly used dictionaries, should be
interpreted as having a meaning which is consistent with their
meaning in the context of the relevant art and the present
disclosure, and will not be interpreted in an idealized or overly
formal sense unless expressly so defined herein.
Exemplary embodiments of the present invention are described herein
with reference to cross section illustrations which are schematic
illustrations of idealized embodiments of the present invention. As
such, variations from the shapes of the illustrations as a result,
for example, of manufacturing techniques and/or tolerances, are to
be expected. Thus, embodiments of the present invention should not
be construed as limited to the particular shapes of regions
illustrated herein but are to include deviations in shapes which
result, for example, from manufacturing. For example, a region
illustrated or described as flat may, typically, have rough and/or
nonlinear features.
Moreover, sharp angles which are illustrated may be rounded. Thus,
the regions illustrated in the figures are schematic in nature and
their shapes are not intended to illustrate the precise shape of a
region and are not intended to limit the scope of the present
invention.
Hereinafter, exemplary embodiments of the present invention will be
described in further detail with reference to the accompanying
drawings.
FIG. 1 is a plan view illustrating an organic light-emitting diode
("OLED") display device according to an exemplary embodiment of the
present invention. FIGS. 2 and 3 are partial cross-sectional views
taken along line I-I' in FIG. 1.
Referring to FIGS. 1 and 2, an OLED display device according to an
exemplary embodiment of the present invention includes an organic
light-emitting substrate part 100 which displays an image and a
protective cover part 200 which protects the organic light-emitting
substrate part 100.
The organic light-emitting substrate part 100 includes a base
substrate 110 and an OLED display portion 120 formed on the base
substrate 110 to display the image thereon.
In an exemplary embodiment, the base substrate 110 has a plate
shape, e.g., a substantially rectilinear shape as shown in FIG. 1,
and includes transparent glass, for example, but alternative
exemplary embodiments are not limited thereto. Further, the base
substrate 110 may include, for example, potassium lime glass, soda
lime glass or quartz glass, but alternative exemplary embodiments
are not limited thereto.
The base substrate 110 includes a display area DA in which the
image is displayed, and a peripheral area PA substantially
enclosing a periphery of the display area DA. As shown in FIG. 1,
the peripheral area PA is formed substantially along an outline,
e.g., a periphery, of the base substrate 110.
The OLED display portion 120 is formed on the base substrate 110
substantially corresponding to a location of the display area DA.
The OLED display portion 120 includes a plurality of unit pixels
(not shown) to display the image.
In an exemplary embodiment, the organic light-emitting substrate
part 100 may further include a protective layer 130 formed on the
base substrate 110 to cover the OLED display portion 120, as shown
in FIG. 2. The protective layer 130 may completely cover the OLED
display portion 120 to protect the OLED display portion 130 or,
alternatively, may cover a portion of the OLED display portion 120.
In an exemplary embodiment, the protective layer 130 includes an
inorganic insulation layer, for example, but alternative exemplary
embodiments are not limited thereto.
FIG. 4 is a schematic circuit diagram illustrating a unit pixel of
an OLED display portion of the OLED display device according to the
exemplary embodiment of the present invention shown in FIG. 1.
Referring to FIG. 4, each unit pixel (not shown) of the OLED
display portion includes a gate line GL, a data line DL, a
switching transistor STFT, a driving transistor DTFT, a bias line
VL, an OLED EL and a storage capacitor SC.
The gate line GL is formed in a first direction, such as a
substantially row or horizontal direction as viewed in FIG. 4, and
the data line DL is formed in a second direction substantially
perpendicular to, e.g., crossing, the first direction in a
substantially column or vertical direction, as shown in FIG. 4.
Further, the bias line VL may be formed to be substantially
parallel to the data line DL formed in the second direction.
The switching transistor STFT is electrically connected to the gate
line GL, the data line DL and the driving transistor DTFT.
Particularly, a gate electrode of the switching transistor STFT is
connected to the gate line GL, a source electrode of the switching
transistor STFT is connected to the data line DL, and a drain
electrode of the switching transistor STFT is connected to the
driving transistor DTFT, as shown in FIG. 4.
The driving transistor DTFT is electrically connected to the drain
electrode of the switching transistor STFT, the bias line VL and
the OLED EL. Specifically, a gate electrode of the driving
transistor DTFT is connected to the drain electrode of the
switching transistor STFT, a source electrode of the driving
transistor DTFT is connected to the bias line VL, and a drain
electrode of the driving transistor DTFT is connected to the OLED
EL.
The OLED EL is electrically connected to the drain electrode of the
driving transistor DTFT and a common voltage terminal Vcom. More
specifically, a first electrode of the OLED EL is connected to the
drain electrode of the driving transistor DTFT, and a second
electrode of the OLED EL is connected to the common voltage
terminal Vcom.
In an exemplary embodiment of the present invention, the storage
capacitor SC is electrically connected between the gate electrode
of the driving transistor DTFT and the bias line VL, as illustrated
in FIG. 4. Thus, a first electrode of the storage capacitor SC may
be connected to the gate electrode of the driving transistor DTFT,
and a second electrode of the storage capacitor SC may be connected
to the bias line VL.
An operating principle of the unit pixel will now be described in
further detail with reference to FIG. 4. When a gate signal is
applied to the gate line GL to turn on the switching transistor
STFT, a data signal from the data line DL is applied to the gate
electrode of the driving transistor DTFT. The data signal is stored
in the storage capacitor SC to turn on the driving transistor DTFT
for one frame, and thus a driving current is applied from the bias
line VL to the OLED EL, and the OLED EL thereby emits light to
display the image.
Referring again to FIGS. 1 and 2, the protective cover part 200
according to an exemplary embodiment of the present invention
includes a first frit glass 230 covering the OLED display portion
120 and a second frit glass 240 formed substantially around the
first frit glass 230.
In an exemplary embodiment, the first frit glass 230 is disposed on
the OLED display portion 120 to completely cover the OLED display
portion 120, as shown in FIG. 1. Further, the first frit glass 230
contacts an upper surface of the protective layer 130 (best shown
in FIG. 2) and covers the OLED display portion 120. A lower surface
of the first frit glass 230 which contacts the upper surface of the
protective layer 130 is substantially flat and smooth in an
exemplary embodiment of the present invention.
The second frit glass 240 is disposed on the base substrate 110
corresponding to the peripheral area PA, and is connected to the
base substrate 110. Further, the second frit glass 240 is formed
around the first frit glass 230, and is also connected to the first
frit glass 230, as shown in FIG. 2.
In an exemplary embodiment, a thickness of the second frit glass
240 is greater than a corresponding thickness of the first frit
glass 230. For example, in an exemplary embodiment, the first frit
glass 230 may have a thickness in a range of approximately 10 .mu.m
to approximately 50 .mu.m, while the second frit glass 240 may have
a thickness in a range of approximately 15 .mu.m to approximately
100 .mu.m. Thus, a range of a thickness difference between the
first frit glass 230 and the second frit glass 240 may be
approximately 5 .mu.m to approximately 50 .mu.m. Further, the
second frit glass 240 according to an exemplary embodiment may have
a width of, approximately 0.5 mm to approximately 2 mm, for
example, such as approximately 1 mm, but alternative exemplary
embodiments are not limited thereto.
The protective cover part 200 may further include a frit cover
layer 220 formed on the first frit glass 230 and the second frit
glass 240 to cover the first frit glass 230 and the second frit
glass 240. In an exemplary embodiment of the present invention for
example, the frit cover layer 220 includes a single layer having an
inorganic insulation layer or, alternatively, a metal layer.
Referring now to FIG. 3, the frit cover layer 220 according to an
alternative exemplary embodiment of the present invention includes
a double layer including an inorganic insulation layer 224 and a
metal layer 222.
The inorganic insulation layer 224 may be formed on the first frit
glass 230 and the second frit glass 240, while the metal layer 222
may be formed on the inorganic insulation layer 224. Alternatively,
the metal layer 222 may be formed on the first frit glass 230 and
the second frit glass 240, and the inorganic insulation layer 224
may be formed on the metal layer 222.
Referring again to FIGS. 1 and 2, the first frit glass 230 and the
second frit glass 240 shield the OLED display portion 120 from
outside elements and/or contaminants, such as external moisture,
for example, to effectively protect the OLED display portion 120
from the same. As a result, in an OLED display device according to
an exemplary embodiment of the present invention, the first frit
glass 230 and the second frit glass 240 water permeation resistance
which effectively blocks the external moisture, or other
contaminants, from infiltrating into the OLED display portion
120.
In an exemplary embodiment, the first frit glass 230 and the second
frit glass 240 may have substantially a same thermal expansion
coefficient as the base substrate 110. Further, the first frit
glass 230 and the second frit glass 240 may each absorb a laser
beam having a wavelength of approximately 800 nm to approximately
820 nm. Melting points of the first frit glass 230 and the second
frit glass 240 in an exemplary embodiment range of approximately
400.degree. C. to approximately 500.degree. C., but alternative
exemplary embodiments are not limited thereto.
In an exemplary embodiment of the present invention, the first frit
glass 230 and the second frit glass 240 include a plurality of frit
powder particles (not shown), frit powder particles of the
plurality of frit powder particles being combined with each other,
and a plurality of filler particles (not shown), filler particles
of the plurality of filler particles being interposed between the
frit powder particles. A concentration of the filler particles in
each of the first frit glass 230 and the second frit glass 240 is
in a range of approximately 10% by weight to approximately 30% by
weight.
The filler particles are interposed between the frit powder
particles to reduce a water reactivity of the first frit glass 230
and the second frit glass 240, and/or to reduce a thermal expansion
coefficient of the first frit glass 230 and the second frit glass
240. In an exemplary embodiment of the present invention, the
filler particles include a crystalline material such as eucryptite,
cordierite, lepidolite or spodumene, for example, but alternative
exemplary embodiments are not limited thereto.
The frit powder particles may include vanadium oxide
("V.sub.2O.sub.5") and/or phosphorous oxide ("P.sub.2O.sub.5"), for
example. In an exemplary embodiment, the frit powder may include
vanadium oxide ("V.sub.2O.sub.5") in a range of approximately 20%
by weight to approximately 45% by weight, and phosphorous oxide
("P.sub.2O.sub.5") in a range of approximately 20% by weight to
approximately 30% by weight.
In an alternative exemplary embodiment, the frit powder particles
may further include zinc oxide ("ZnO"), bismuth oxide
("Bi.sub.2O.sub.3"), boron oxide ("B.sub.2O.sub.3"), iron oxide
("Fe.sub.2O.sub.3"), aluminum oxide ("Al.sub.2O.sub.3") and/or
silicon oxide ("SiO.sub.2"), for example.
Further, the frit powder particles may include a first oxidized
substance which increases an adhesive strength and a second
oxidized substance which stabilizes glass. Examples of the first
oxidized substance include lithium oxide ("Li.sub.2O"), sodium
oxide ("Na.sub.2O"), potassium oxide ("K.sub.2O") and cesium oxide
("Cs.sub.2O"), for example, while examples of the second oxidized
substance include magnesium oxide ("MgO"), calcium oxide ("CaO"),
strontium oxide ("SrO") and barium oxide ("BaO"), for example.
Thus, as described above, the protective cover part 200 including
the first frit glass 230 and the second frit glass 240 having water
permeation resistance is disposed on the base substrate 110 to
completely cover the OLED display portion 120. Thus, the first frit
glass 230 and the second frit glass 240 effectively shield the OLED
display portion 120 from the external moisture and/or other
contaminants to effectively protect the OLED display portion 120
from the same. As a result, a cover substrate for protecting the
OLED display portion may be omitted in the OLED display device
according to an exemplary embodiment of the present invention.
Hereinafter, a method of manufacturing an OLED display device
according to an exemplary embodiment of the present invention will
be described in further detail with reference to FIGS. 5 through
15. The same reference characters in FIGS. 5 through 15 refer to
the same or like components as described above with respect to
FIGS. 1 through 4, and any repetitive detailed description thereof
will hereinafter be omitted.
FIG. 5 is a partial cross-sectional view illustrating a process of
forming an organic light-emitting substrate part of the OLED
display device according to the exemplary embodiment of the present
invention shown in FIG. 1.
Referring to FIG. 5, the OLED display portion 120 is formed on the
base substrate 110 corresponding to the display area DA (FIG. 2).
The OLED display portion 120 according to an exemplary embodiment
of the present invention may include a plurality of layers formed
through a plurality of deposition and etching processes.
Then, the protective layer 130 is formed on the base substrate 110
to cover the OLED display portion 120. In an exemplary embodiment
of the present invention, the protective layer 130 may be
omitted.
FIGS. 6 and 7 are partial cross-sectional views illustrating a
process of forming a frit cover layer on a cover substrate of an
OLED display device according to an exemplary embodiment of the
present invention.
Referring to FIGS. 6 and 7, the frit cover layer 220 is formed on a
cover substrate 210.
In an exemplary embodiment, the frit cover layer 220 includes a
single layer, e.g., the inorganic insulation layer 224 or the metal
layer 222, or, alternatively, may include a double layer such as
the inorganic insulation layer 224 and the metal layer 222.
When the frit cover layer 220 includes the double layer, the metal
layer 222 may be first formed on the cover substrate 210, and
thereafter the inorganic insulation layer 224 may be formed on the
metal layer 222, as shown in FIG. 7, but alternative exemplary
embodiments of the present invention are not limited thereto.
The cover substrate 210 according to an exemplary embodiment may
have a plate shape, e.g., a substantially rectilinear shape, and
may include a material such as transparent glass, for example. In
addition, the cover substrate 210 may include substantially a same
material as of the base substrate 110.
FIG. 8 is a partial cross-sectional view illustrating a process of
forming a first frit glass on the frit cover layer of the OLED
display device according to the exemplary embodiment of the present
invention shown in FIG. 6.
Referring to FIG. 8, after the frit cover layer 220 is formed, the
first frit glass 230 is formed on an area of the frit cover layer
220 corresponding to the display area DA.
To form the first frit glass 230, a first frit paste is formed on
the frit cover layer 220, and thereafter the first frit paste is
dried and then fired to form the first frit glass 230. In an
exemplary embodiment of the present invention, the first frit paste
has viscosity, e.g., is a fluid.
According to an exemplary embodiment, the first frit paste is
formed by using a spray unit (not shown) or, alternatively, by
using a silkscreen method. The first frit paste includes a
plurality of frit powder particles, a plurality of binder particles
interposed between the frit powder particles, a plurality of filler
particles interposed between the frit powder particles, and a
solvent which dissolves the frit powder particles, the binder
particles and the filler particles.
To dry and fire the first frit paste, the first frit paste is dried
at a first temperature, thereby removing the solvent. Then, the
first frit paste, the solvent having been removed therefrom, is
fired at a second temperature, the second temperature being greater
than the first temperature, to remove the binder particles. In an
exemplary embodiment, an outer surface of the first frit paste is
maintained substantially flat and smooth through the firing
process.
According to an exemplary embodiment of the present invention, the
first temperature is in range of approximately 180.degree. C. to
approximately 220.degree. C., and may be, for example, specifically
at approximately 200.degree. C. The second temperature, on the
other hand, is in a range of approximately 400.degree. C. to
approximately 600.degree. C. and, specifically, may be in a range
of approximately 450.degree. C. to approximately 500.degree. C.,
but alternative exemplary embodiments are not limited thereto.
FIG. 9 is a partial cross-sectional view illustrating a process of
forming a second frit glass on the frit cover layer of the OLED
display device according to the exemplary embodiment of the present
invention shown in FIG. 7.
Referring to FIG. 9, after the first frit glass 230 is formed, the
second frit glass 240 is formed substantially around the first frit
glass 230.
In order to form the second frit glass 240, a second frit paste is
formed on the frit cover layer 220 and is connected to an outline,
e.g., a periphery, of the first frit glass 230. Thereafter, the
second frit paste is dried and fired to form the second frit glass
240. In an exemplary embodiment of the present invention, the
second frit paste has viscosity, e.g., is a fluid.
In an exemplary embodiment, the second frit paste is formed by
using a spray unit (not shown) or, alternatively, by using a
silkscreen method. In addition, the second frit paste may include
substantially the same or like elements as the first frit
paste.
Specifically, the second frit paste may include a plurality of frit
powder particles, a plurality of binder particles interposed
between the frit powder particles, a plurality of filler particles
interposed between the frit powder particles, and a solvent which
dissolves the frit powder particles, the binder particles and the
filler particles.
To dry and fire the second frit paste, the second frit paste is
first dried at the first temperature to remove the solvent
therefrom. Then, the second frit paste, from which the solvent has
been removed, is fired at the second temperature to remove the
binder particles therefrom.
In an exemplary embodiment, after the first frit paste is dried and
fired to form the first frit glass 230, the second frit paste is
dried and fired to form the second frit glass 240, but alternative
exemplary embodiments of the present invention are not limited
thereto. For example, the first frit paste may be dried and fired
to form the first frit glass 230 after the second frit paste is
dried and fired to form the second frit glass 240.
In yet another alternative exemplary embodiment, the first frit
paste and the second frit paste may be simultaneously dried and
fired to form the first frit glass 230 and the second frit glass
240, respectively, after the first frit paste and the second frit
paste are continuously formed on the frit cover layer 220.
FIGS. 10A and 10B are partial cross-sectional views illustrating
internal states, before and after firing, respectively, of both the
first frit glass and the second frit glass according to the
exemplary embodiment of the present invention shown in FIGS. 8 and
9.
Referring to FIGS. 10A and 10B, when the first frit paste and the
second frit paste are dried at the first temperature (FIG. 10A) and
are then fired at the second temperature (FIG. 10B), frit powder
particles 250 in the first frit paste and the second frit paste are
combined, e.g., an effective density of the frit powder particles
250 between filler particles 255 is increased, as shown in FIG. 10B
(in comparison to as shown FIG. 10A).
Thus, although the solvent and the binder particles are removed
through the drying and firing processes, the first frit glass 230
and the second frit glass 240 are densely combined, e.g., are
formed without being porous, due to the combining of the frit
powder particles 250 between the filler particles 255.
FIG. 11 is a partial cross-sectional view illustrating a process of
applying a laser beam to both the first frit glass and the second
frit glass of the OLED display device according to the exemplary
embodiment of the present invention shown in FIG. 9.
Referring to FIG. 11, after the first frit glass 230 and the second
frit glass 240 are formed, the second frit glass 240 is partially
cured, e.g., a portion of the second frit glass 240 is cured,
while, in contrast, the first frit glass 230 is completely cured,
e.g., the entire the first frit glass 230 is cured.
Specifically, a laser beam 15 is applied to a boundary area 245
between the first frit glass 230 and the second frit glass 240, as
well as an entire area of the first frit glass 230 using a curing
laser 10. Thus, a portion of the second frit glass 240, e.g., the
boundary area 245, and all of the first frit glass 230 are
temporarily melted by the laser beam 15 and thereafter cured again,
and are thereby strongly combined with each other and with the frit
cover layer 220. External moisture, e.g., external water, is
effectively prevented from permeating to the interior of the OLED
display portion 120, since a portion of the second frit glass 240
nearest the OLED display portion 120, e.g., the boundary area 245,
as well as all of the first frit glass 230, are cured by the laser
beam 15.
FIG. 12 is a partial cross-sectional view illustrating a process of
coupling the organic light-emitting substrate part of the OLED
display device according to the exemplary embodiment of the present
invention shown in FIG. 5 to the protective cover part of the OLED
display device according to the exemplary embodiment of the present
invention shown in FIG. 11.
Referring to FIG. 12, after the protective cover part 200 including
the cover substrate 210, the frit cover layer 220 the first frit
glass 230 and the second frit glass 240 are formed, the protective
cover part 200 is coupled to the organic light-emitting substrate
part 100.
To couple the protective cover part 200 to the organic
light-emitting substrate part 100, the protective cover part 200 is
first aligned with the organic light-emitting substrate part 100 so
that the OLED display portion 120 is substantially covered by the
first frit glass 230.
Then, the organic light-emitting substrate part 100 and the
protective cover part 200 are vacuum-compressed. When the organic
light-emitting substrate part 100 and the protective cover part 200
are vacuum-compressed, the protective cover part 200 makes a strong
contact with the organic light-emitting substrate part 100.
FIG. 13 is a partial cross-sectional view illustrating a process of
applying a laser beam to the second frit glass of the OLED display
device according to the exemplary embodiment of the present
invention shown in FIG. 12. FIGS. 14A and 14B are partial
cross-sectional views of area "A" in FIG. 13, illustrating internal
states, before and after applying the laser beam, respectively, of
the second frit glass f the OLED display device according to the
exemplary embodiment of the present invention shown in FIG. 13
before and after applying the laser beam, respectively.
Referring to FIGS. 13, 14A and 14B, a laser beam 15 is applied to
the second frit glass 240 to strongly couple the second frit glass
240 to the base substrate 110.
Specifically, a curing laser 10 is disposed above to the second
frit glass 240, and the laser beam 15 is applied to the second frit
glass 240 using the curing laser 10. When the laser beam 15 is
applied to the second frit glass 240, a portion 242 of the second
frit glass 240, e.g., the boundary area 245 (best shown in FIG.
11), is temporarily melted and is thereafter cured again, to be
strongly combined with the base substrate 110. Thus, the OLED
display portion 120 is effectively sealed by the cured first frit
glass 230 and the second frit glass 240, and the OLED display
device according to an exemplary embodiment of the present
invention is thereby protected from the external water, e.g.,
moisture.
In an exemplary embodiment, the portion 242 of the second frit
glass 240, to which the laser beam 15 is applied, may include an
uncured portion of the second frit glass 240 that is previously not
cured, such as a portion of the second frit glass opposite the
boundary area 235 (best shown in FIG. 11). In an exemplary
embodiment, a width of the portion 242 of the second frit glass
240, to which the laser beam 15 is applied, has a range of
approximately 60% to approximately 70% of an entire width of the
second frit glass 240. For example, when the entire width of the
second frit glass 240 is approximately 1 mm, the width of the
portion 242 of the second frit glass 240, to which the laser beam
15 is applied, has a range of approximately 0.6 mm to approximately
0.7 mm.
In an exemplary embodiment, the curing laser 10 is a diode laser,
and a wavelength of the laser beam 15 is in a range of
approximately 800 nm to approximately 820 nm. Further, the diode
laser may generate a laser beam 15 having a power level of
approximately 50 W.
In an exemplary embodiment, when the laser beam 15 is applied to
the second frit glass 240, gas, which has an adverse influence on
the OLED display portion 120, is generated from the second frit
glass 240. However, the gas does not move to the OLED display
portion 120, since the boundary portion 245 between the first frit
glass 230 and 240, as well as all of the first frit glass 230, are
already cured. Thus, the OLED display portion 120 according to an
exemplary embodiment of the present invention is effectively
protected from the gas.
FIG. 15 is a partial cross-sectional view illustrating a process of
separating the cover substrate of the OLED display device according
to the exemplary embodiment of the present invention shown in FIG.
14 from the first frit glass and the second frit glass.
Referring to FIG. 15, after the protective cover part 200 is
coupled, e.g., is connected, to the organic light-emitting
substrate part 100, as described in greater detail above, the cover
substrate 210 is separated from the first frit glass 230 and the
second frit glass 240.
To separate the cover substrate 210 from the first frit glass 230
and the second frit glass 240, a laser beam 25 is first generated
using a substrate separating laser 20 and is thereby irradiated
onto an entire area of the frit cover layer 220. As a result, the
cover substrate 210 is separated from the first frit glass 230 and
the second frit glass 240.
In an exemplary embodiment of the present invention, the frit cover
layer 220 includes a double layer including the metal layer 222 and
the inorganic insulation layer 224 (best shown in FIG. 7). As a
result, the metal layer 222 absorbs energy, e.g., heat, from the
laser beam 25 well to easily separate the cover substrate 210 from
the first frit glass 230 and the second frit glass 240.
When the laser beam 25 is applied to the frit cover layer 220, the
frit cover layer 220 is temporarily transformed into a melted
state, and the cover substrate 210 may thereby be easily separated
from the first frit glass 230 and the second frit glass 240. The
cover substrate 210, separated by the laser beam 25, may be cleaned
and reused.
In an exemplary embodiment of the present invention, the substrate
separating laser 20 is an neodymium-doped yttrium aluminum garnet
("Nd:YAG") laser. Further, the laser beam 25 may have a wavelength
of approximately 1,050 nm to approximately 1,070 nm. Specifically,
the laser beam 25 according to an exemplary embodiment has a
wavelength of approximately 1,064 nm.
As described above, the first frit glass and the second frit glass
of and OLED display device according to an exemplary embodiment of
the present invention cover and protect the OLED display portion of
the OLED display device. Thus, a cover substrate, required in an
OLED display device of the prior art, may be omitted, and a
manufacturing cost of the OLED display device according to an
exemplary embodiment of the present invention is substantially
reduced.
In addition, gas generated from the second frit glass is
effectively prevented from flowing to the OLED display portion.
Thus, the OLED display portion is effectively protected from the
gas and adverse affects therefrom are substantially reduced and/or
effectively eliminated in the OLED display device according to
exemplary embodiments of the present invention.
As described and shown herein, according to exemplary embodiments
of the present invention, a protective cover part including a first
frit glass and a second frit glass completely covers and protects
an OLED display portion of an OLED display device. Thus, a cover
substrate required in an OLED display device of the prior art may
be omitted in the OLED display device according to exemplary
embodiments of the present invention, and manufacturing costs of
the OLED display device according to exemplary embodiments of the
present invention are substantially reduced.
The present invention should not be construed as being limited to
the exemplary embodiments set forth herein. Rather, these exemplary
embodiments are provided so that this disclosure will be thorough
and complete and will fully convey the concept of the present
invention to those skilled in the art.
Although exemplary embodiments of the present invention have been
described herein, it will be understood by those of ordinary skill
in the art that various changes and modifications in form and
detail may be made therein without departing from the spirit or
scope of the present invention as defined by the following
claims.
* * * * *